This invention relates to vehicle friction brakes and particularly, but not exclusively, to such brakes for bicycles.
When driving or riding a vehicle in wet or dirty conditions, water or dirt on one or more of the braking surfaces can cause a significant reduction in braking efficiency.
According to one aspect of the present invention, there is provided a component for a vehicle friction brake comprising a main body, a scraper element, and a flexible hinge portion connecting the main body to the scraper element, the main body, scraper element and hinge portion being formed integrally of plastic material, the scraper element being adapted to flex about the hinge portion between a rest position and a deflected position in which the hinge portion acts to bias the scraper element towards the rest position, the scraper element being adapted to be arranged to contact a surface of a member to be braked upstream of a braking member of the brake and, in the rest position and upon initial operation of the brake, to move into contact with the surface before the braking member contacts the surface and, upon further operation of the brake, as the braking member is moved into contact with the surface, to flex against the bias of the hinge portion to bias the scraper element into contact with the surface of the member to be braked.
The scraper element and the main body are advantageously substantially rigid, with flexing being confined to the hinge portion in the deflected position of the scraper element.
A portion at least of the scraper element may be adapted to be arranged to extend both towards the surface of the member to be braked and in a direction upstream of the braking member of the brake. The scraper element may comprise an end portion which is inclined relative to the direction of extent of the scraper element to form an apex at the leading edge of the scraper element end surface.
This scraper element end surface may be generally planar and adapted to be arranged to be generally parallel to the surface of the member to be braked as the brake is operated. At least a portion of this end surface may be arranged to extend beyond the plane of the operative surface of the braking member towards the surface of the member to be braked.
The scraper element may be adapted to be arranged to flex in a direction away from the surface of the member to be braked when the brake is further operated.
Stop means are preferably provided on at least one of the scraper element and the main body for limiting flexing of the scraper element about the hinge portion. These stop means advantageously comprise two projections associated with the hinge portion, the projections being arranged to have a gap therebetween in the rest position of the scraper element and to be brought into abutment in the fully deflected position of the scraper element.
The main body preferably forms a mounting member for mounting the component on the brake.
The material of the hinge portion may be of reduced thickness relative to the adjoining material of the main body and the scraper element.
The component may form part of the braking member. Alternatively, the component may be provided separately of the braking member and be adapted for attachment to the braking member to move with the braking member towards the surface of the member to be braked as the brake is operated. Means for attaching the component to the braking member or brake may comprise two walls integrally formed with the main body and depending from the main body to form a generally U-shaped channel adapted to receive at least a part of the braking member. Preferably one or more projections is provided on the walls, projecting into the channel and arranged, in use, to engage the braking member to assist attachment of the component to the braking member.
Where a portion of the main body forms a base to the channel, the portion may be apertured to allow securing means, for securing the braking member to the brake, to pass therethrough. This aperture is preferably shaped to conform generally to the shape of the base of the securing means to provide additional location of the component relative to the braking member.
According to a further aspect of the present invention, there is provided a braking apparatus for a vehicle friction brake comprising a braking member and a component in accordance with the above-recited first aspect of the present invention.
According to a yet further aspect of the present invention, there is provided a vehicle friction brake comprising a brake caliper, each arm portion of the caliper being provided with at least one braking apparatus in accordance with the above-recited further aspect of the present invention, wherein the braking member of each braking apparatus is attached to its respective caliper arm portion.
An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings.